How do you pronounce KAOSH®? 

I called linguistics expert, Prof. Sandra Disner, Ph.D. a number of years ago, and asked her that very question.  Nothing worse than coming up with a brand name, and not know how to say it!  Dr. Disner concluded that, in American English, it’s pronounced “K-osh”, with the ‘osh’ sound the same as it is in posh, mosh, etc.